The invention relates to an hour gear structure of a watch drive mechanism wherein the hour gear structure includes a bearing sleeve on which an hour hand is disposed and which serves as bearing for the minute gear.
Since the hour gear of a watch operating mechanism rotates only once per hour there is no need to provide an expensive bearing structure for the hour gear. Rather the hour gear is generally simply mounted on a bearing sleeve or it is formed integral with the bearing sleeve and the bearing sleeve is disposed in a corresponding bore in the operating mechanism base plate such that the center collar with which the gear is provided abuts the base plate. A minute gear structure shaft is supported centrally within the sleeve-type hour gear shaft and is additionally supported at its end opposite the minute hand by way of a trunnion which extends into a bearing in a gear shaft support plate spaced from, and parallel to, the base plate.
With watch operating mechanisms of generally the same type there is sometimes the need to provide for a shaft sleeve of the hour gear as well as the minute gear shaft which are shorter or possibly longer in some than in other operating mechanisms in production such that the sleeve shaft projects from the base plate to a smaller or greater extent. This requires the manufacture of a different minute gear structure and heretofore also the manufacture of a different hour gear structure including the sleeve shaft.